The present invention relates to a wiper arm and a window wiper device, in particular for a motor vehicle.
Numerous wiper arms for window wiping devices with a four-joints are known, as disclosed for example in the German patent document DE 44 44 066 A1. The wiper arm is composed in this window wiping device of a joint part on which at least indirectly a wiper blade is arranged, and a mounting part which connects the wiper arm with the wiper shaft which is swingingly movable during the operation. The mounting part is composed substantially of a short elongated portion which at one end is rotatably connected with the hinge part. Two cranks are coupled to the mounting part. One of the cranks is swingly driven by a wiper drive, while the other crank is permanently connected with the window wiping device or the vehicle chassis and serves for a stroke generation.
Since great forces must be transmitted between the cranks and the mounting part, the cranks and the mounting part must be formed in this region especially stable and therefore must have a relatively great structural high.
Accordingly, it is an object of the present invention to provide a wiper arm, as well as a window wiping device for a motor vehicle which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated in a wiper arm in which the mounting part has at least a first plate and a second plate arranged substantially parallel to it, and at least one of the cranks is rotatably mounted between the plates.
When the wiper arm is designed in accordance with the present invention, then due to the arrangement of the both cranks between two plates of the mounting part, a small structural height of the wiper arm is obtained. Therefore the aerodynamics of the window wiping device is improved and wind noise on the window wiping device is reduced.
In accordance with a further feature of the present invention the both plates are connected with one another by a spacer piece. Therefore, the bearing forces are reduced and the service life of the wiper arm is further increased.
It is especially advantageous when in accordance with a further feature of the present invention one of the plates has a pocket or an opening, in which a pin engages, being rotatably supported by one of the cranks. Thereby the pin is reliably held between the plates and can be easily used in the mass production.
The pin can extend through one of the plates over its full length and can be mounted at the side of the plate which faces away from the crank.
The pin obtains a reliable hold and can be produced in the mass production in a simple manner, for example by insertion and riveting on the plate.
It is especially advantageous when in accordance with another feature of the present invention at least one of the plates is formed as a cast part. Cast parts are manufactured in a cost favorable manner, and pockets for receiving the pins or spacer members can be integrated simply in the plate, due to a significant freedom during the molding.
Furthermore, it is advantageous when at least one pin is pressed in a ball bearing, and the ball bearing is pressed in a recess in the crank. In this way the bearing is directly integrated in the crank so that the structural height can be further reduced. In accordance with another feature of the present invention a window wiper device is proposed, which includes a window wiping device for a motor vehicle, comprising a wiper arm; a wiper blade supported by said wiper arm; and means for moving said wiper arm relative to a window of a vehicle, said wiper arm including a first crank and a second crank, a mounting part which is mountable by said first crank and said second crank in two points, said mounting part having at least a first plate and a second plate arranged substantially parallel to one another, at least one of said cranks being mounted rotatably between said plates.
When the window wiping device is designed in accordance with the present invention it is easily mountable in a vehicle and has a low structural height of its wiper arm.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.